The present invention relates to stethoscopes. More particularly, it relates to stethoscopes in which the bell may be reduced in diameter to better accomodate diminutive skin areas.
The chest piece of most medical stethescopes are of the so-called dual-head type having opposed diaphragm and open bell sides which are adapted for detecting high frequency and low frequency sounds, respectively. Dual-head stethoscopes of this type are described, for example, in U.S. Pat. Nos. 3,108,652; 3,152,659; 3,215,224; 3,224,526; 3,276,536; 3,303,903; 3,366,198; and 3,515,239.
Problems are frequently encountered when the bell side of conventional stethoscope chest pieces are used on pediatric patients or on skin areas of high curvature. In such cases, it is many times difficult to acoustically seal the rim of the open bell with the underlying skin.
U.S. Pat. No. 3,223,195 discloses a stethoscope head construction comprising a double ended receiver having a large bell at one end, a small bell at its distal end and a core which is shiftable to successfully implement the operative condition of either of these bells. The large bell is said to be intended for low frequency range reception of sound, and the small bell is intended for high amplitude low frequency sound reception. The small bell also is described as suitable for use on "bony" type chests and in pediatrics and for listening to small localized areas of a chest. The stethoscope head construction is relatively complicated and not believed to conveniently adapt a conventional stethoscope chest piece for use on pediatric patients and areas of high curvature.